The invention relates to a particle beam blanking system according to the preamble of claim 1 and comprising deflection means for effecting the blanking of a particle beam.
For many particle beam apparatus, generation of short particle pulses with steep leading edges is necessary without a movement of the particle probe taking place in the image, or in the object plane, respectively. Particularly, in the area of electron beam measurement technique, for the purpose of carrying out stroboscopic methods, electron pulses with steep leading edges are necessary in order to obtain high chronological and local resolution in the case of analysis of test objects with rapidly variable operational data. A particle beam blanking system of the type initially cited can be advantageously employed, for example, in the case of an electron beam apparatus and in the case of a measurement method such as are described in U.S. Pat. No. 4,277,679.
In the case of the known stroboscopic electron beam apparatus according to the state of the art, a relatively simple plate deflection system is activated with blanking pulses as rectangular as possible. The problem of brief time-particle beam pulse generation was thus shifted to the construction of extremely rapid, electric pulse generators for the purpose of activation of the plate deflection system. A movement of the particle beam probe on the surface of a test object could thus not be avoided. The consequences thereof are a relatively poor chronological and local resolution during the analysis of processes, varying rapidly chronologically and spatially, on the surface of the test subject and, as the consequence of this, an impairment of measurement results. If, with the aid of stroboscopic measuring methods in the case of electron beam measuring technique, a surface (coated with a passivation layer) of an electronic component is to be examined, the movement of an electron beam probe on the passivation layer brings about an additional charge of said passivation layer, and hence an additional impairment of the measurement (or test) results.
Further background concerning the use of a scanning electron microscope for measuring the quantitative potential and waveform at a measuring location of an electronic component such as an integrated circuit is found in an article by Feuerbaum and Hernaut entitled "Application Of Electron Beam Measuring Techniques For Verification Of Computer Simulations For Large-Scale Integrated Circuits" in Scanning Electron Microscopy 1978, Vol. I, at pages 795-800.